Vue SDK reference
Read time: 3 minutes
Last edited: May 12, 2023
Overview
This topic documents how to get started with the Vue SDK.
LaunchDarkly's SDKs are open source. In addition to this reference guide, we provide source, API reference documentation, and a sample application:
Resource | Location |
---|---|
SDK API documentation | SDK API docs |
GitHub repository | vue-client-sdk |
Sample application | Vue |
Published module | npm |
The Vue SDK builds on LaunchDarkly's JavaScript SDK to provide a better integration for use in Vue applications. As a result, much of the JavaScript SDK functionality is also available for the Vue SDK to use. For a complete client-side JavaScript SDK reference, read JavaScript SDK reference.
The LaunchDarkly Vue SDK only works with Vue 3.
For Vue 2 projects, you can use the JavaScript SDK directly, or a community developed package such as vue-ld.
Getting started
After you complete the Getting started process, follow these instructions to start using the LaunchDarkly SDK in your Vue project.
You must make feature flags available to client-side SDKs before the SDK can evaluate those flags. If an SDK tries to evaluate a feature flag that is not available, the user will receive the fallback value for that flag.
To make a flag available to this SDK, check the SDKs using Client-side ID checkbox during flag creation, or on the flag's Settings tab. To make all of a project's flags available to this SDK by default, check the SDKs using Client-side ID checkbox in your project Settings.
To install the Vue SDK, you need your LaunchDarkly environment's client-side ID.
To find and copy your LaunchDarkly client-side ID:
- Navigate to the Account settings page.
- Click the Projects tab.
- Click the name of your project. The Environments tab appears.
- Click the environment's client-side ID to copy it to your clipboard.
Client-side IDs are not secret and you can expose them in your client-side code without risk. However, never embed a server-side SDK key into a client-side application.
Install the Vue SDK using either npm
or yarn
:
npm install --save launchdarkly-vue-client-sdk
After you install the dependency, add the LaunchDarkly plugin to your Vue app. Typically you do this in main.js
:
import { createApp } from 'vue'import App from './App.vue'import { LDPlugin } from 'launchdarkly-vue-client-sdk'const clientSideID = 'client-side-id-123abc'const app = createApp(App)app.use(LDPlugin, { clientSideID })app.mount('#app')
Configuring the Vue SDK
The SDK provides a Vue plugin that you can add to your app. You can pass configuration options to the plugin when it loads, or to the ldInit
function if you are using the deferInitialization
option. To learn more, read Initializing the client. To learn more about the available configuration options, read LDPluginOptions.
Using the plugin
The plugin exposes the LaunchDarkly client, as well as some convenience functions. As it uses the Vue provide/inject API to do this, these functions will only work when run within Vue's setup hook or <script setup>
. To learn more, read Provide/Inject.
Initializing the LaunchDarkly client
The SDK automatically initializes the LaunchDarkly client if you provide a clientSideID
, and do not use the deferInitialization
option. Otherwise, you will need to initialize the LaunchDarkly client manually with ldInit
, which accepts the same options
as the plugin.
For example, if you do not know your user at plugin load time and need to defer initialization until you do, you can use the deferInitialization
option.
Here's how:
import { createApp } from 'vue'import App from './App.vue'import { LDPlugin } from 'launchdarkly-vue-client-sdk'const app = createApp(App)app.use(LDPlugin, { clientSideID: 'client-side-id-123abc', deferInitialization: true })app.mount('#app')
To learn more, read the API documentation for ldInit.
Use ldReady
to check when the LaunchDarkly client has finished initializing. This is returned by ldInit
. You can also retrieve it independently with useLDReady
. ldReady
is a ref, so to access its value outside of a template you need to use ldReady.value
.
Here's how:
<script setup lang="ts">import { useLDReady } from 'launchdarkly-vue-client-sdk'const ldReady = useLDReady()</script><template><div v-if="ldReady">... content that uses LaunchDarkly ...</div><div v-else>LaunchDarkly client initializing...</div></template>
Retrieving flag values with the client
Use useLDFlag
to access a single flag value by key. It returns a readonly ref for the value of a flag. If you are using TypeScript, the ref's type can be inferred from the type of the fallback value provided to useLDFlag
. To learn more about Vue refs, read ref in the Vue.js documentation.
Example usage:
<script setup lang="ts">import { useLDFlag } from 'launchdarkly-vue-client-sdk'const featureFlagKey = 'my-boolean-flag'const myFlagValue = useLDFlag(featureFlagKey, false /* default flag value */)</script><template>Feature flag "{{ featureFlagKey }}" has value "{{ myFlagValue }}".</template>
The Vue SDK automatically subscribes to flag change events with useLDFlag
, and your component re-renders automatically when flag changes occur. This is a benefit of useLDFlag
as compared with getting flag values using the underlying JavaScript SDK, for example with ldClient.variant()
or ldClient.allFlags()
. If you do not want flag updates streamed to your application, you can disable this by including the streaming: false
option when loading the plugin or calling ldInit
.
To learn more, read the API documentation for useLDFlag.
You may also access the LaunchDarkly client with useLDClient
, the LDClient object from the underlying JavaScript SDK.
Here is an example:
import { useLDClient } from 'launchdarkly-vue-client-sdk'const ldClient = useLDClient()const allFlags = ldClient.allFlags()
Example app
An example app is included in launchdarkly/vue-client-sdk.
git clone git@github.com:launchdarkly/vue-client-sdk.gitcd vue-client-sdknpm inpm start